A sensor is a device that can detect and capture physical quantities (such as temperature, pressure, light intensity, displacement, etc.) or chemical quantities (such as gas concentration, humidity, etc.) in the external environment. Its core function is to convert these non-electrical signals into electrical signals (such as voltage, current) that can be processed by electronic systems, thereby providing feedback on environmental conditions or equipment operation status to processors, control systems, etc. As a key interface for interaction between electronic systems and the external world, it enables various devices to achieve automatic sensing and intelligent response.